Bataller ? UO1 (RFA AA-18-003) ABSTRACT Hepatocellular failure is a hallmark finding in patients with alcoholic hepatitis (AH). Current therapy is not fully effective and targeted therapies are needed. Most research has been focused on the role of inflammation. In contrast, the mechanisms underlying hepatocellular failure and the subsequent poor regenerative response in AH are unknown. Our group showed that severe AH is characterized by a massive, yet inefficient accumulation of ductular cells. The central aim of this proposal is to identify the molecular mechanisms underlying the hepatocellular failure and the subsequent poor regenerative response in AH. The ultimate goal is the identification of prognostic markers and therapeutic targets useful for precision medicine. We have generated strong preliminary data in human livers showing: (1) progression of early forms of ALD to AH is characterized by a profound decrease in the function of HNF4A. (2) HNF4A network footprint closely correlates with disease severity in AH patients. (3) TGF?1 and EGF are key upstream modulators in AH and regulate LETF in cultured human hepatocytes. (4) The gene signature of the ductular reaction in AH shows enriched inflammatory, fibrogenic and proliferative signals and decreased HNF4A activity. And (5) Secreted proteins encoded by LEFT-target genes are detected in sera of patients with AH. Based on these strong preliminary data, our specific aims are (1) To uncover the molecular mechanism of HNF4A isoform regulation by TGF?1, by characterizing the interactome of the HNF4A P1 dependent isoforms by MS coupled Immunoprecipitation. Moreover, we aim at identifying the DNA binding regions of HNF4A P2 isoform by ChIPseq, and generating a promoter reporter system that will be used for in vitro high- troughput screening of novel drugs. (2) To investigate the relevance and genomic profile of ductular proliferation and de-differentiated hepatocytes in AH by means of RNAseq of microdissected areas and correlation of gene signatures with clinical outcome. We have developed human organoids of ductular reaction that represents a novel tool to study the effect of TGF?1 and EGFR ligands in HNF4A. And (3). To identify new serum protein biomarkers of AH by investigating serum N-linked glycoprotein compartment by glycoprotein selection coupled to MS and by analyzing post-translational modifications of the serum proteome by Snap-shot proteomic array. We will combine analysis of serum proteomic data with transcriptomic studies of total and microdissected liver tissue and correlate the resulting signatures with clinical outcomes including mortality and response to prednisolone and G-CSF.